What’s the surest way to tell an independent film from a big-studio production? Hollywood won’t show a dog being killed, but gritty indie helmers don’t hesitate. (Don’t worry — it’s only a movie.) In “Red,” bad-seed teens torment a benign old man (Brian Cox) and shoot his beloved 14-year-old pooch, bringing serious bad karma. Rather than leveraging its central tragedy to support a mindless exercise in style, “Red” serves as a throwback to the no-gloss psychological tack of “Walking Tall” and other ’70s exploitation classics. Still, most auds won’t pay to see such cruelty, animal or otherwise, severely limiting this thriller’s reach.

Touchy subject matter aside, “Red” demonstrates real elegance in its commitment to a relatively straightforward story, allowing the characters’ emotions to come to a slow boil. As far as creative integrity goes, it’s hard to do better than building a project around an actor of Cox’s caliber. In small-town general store operator Avery Ludlow, Cox suggests both the character’s gentle nature and the angry tempest welling beneath the surface, carrying entire scenes in closeup.

The film is anchored to Ludlow’s experience, and it works insofar as auds can identify with his actions. When he confronts the killer’s father (Tom Sizemore), there’s instant satisfaction in seeing this blue-collar everyman stand up to his nouveau-riche adversary, but later on, when Ludlow foolishly puts himself in harm’s way, it seems as if the genre gears have taken over.

Along the way, the movie drops hints about his backstory, which involves a shocking family tragedy that explains not only Ludlow’s attachment to Red but also his interest in redeeming the troubled young man who pulled the trigger.

Screenwriter Stephen Susco communicates with a wisdom beyond his years, injecting moments of profound introspection, both spoken and silent. And yet, there remains a certain clumsiness in even the most rudimentary plot developments, such as Ludlow’s awkward friendship with a sympathetic local newscaster (Kim Dickens).

Perhaps the unevenness owes to the project’s mongrel roots: “Red” was initiated by American director Lucky McKee and completed by Norwegian helmer Trygve Allister Diesen. Tone is absolutely critical in pulling off a story like this, lest the material veer into sentimentality or schlock, and to their mutual credit, “Red” feels seamless in that regard.

Low-key score emphasizes Ludlow’s state of mind, while Harald Gunnar Paalgard’s HD compositions tend to be functional rather than flashy (with a few artistic exceptions, as in a shot that lingers on Cox’s eye as he exits Sizemore’s office). Thoughtful approach notwithstanding, horror hounds are sure to appreciate this niche offering more than dog-lovers will.